[Influence of Immunohistochemistry Scoring Criteria in Detecting EGFR Mutations]

CircRNA_000864 Upregulates B-cell Translocation Gene 2 Expression and Represses Migration and Invasion in Pancreatic Cancer Cells by Binding to miR-361-3p

Background

Pancreatic cancer is a fatal disease with a very poor prognosis due to its characteristic insidious symptoms, early metastasis, and chemoresistance. Circular RNAs (circRNAs) are involved in the development of pancreatic cancer.

Aim

Hence, the aim of this study is to elucidate the mechanism of circRNA_000864 in regulating BTG2 expression in pancreatic cancer by binding to miR-361-3p.

Methods

CircRNA_000864, miR-361-3p, and BTG2 expression patterns in the pancreatic cancer tissues were detected by RT-qPCR. Correlation among circRNA_000864, miR-361-3p, and BTG2 was evaluated by RNA-pull down assay, RNA Immunoprecipitation assay, and dual-luciferase reporter gene assay. After ectopic expression and depletion experiments, 5-ethynyl-2′-deoxyuridine assay, Transwell assay, and flow cytometry were employed to assess the cell proliferation, migration and invasion, cell cycle, and apoptosis. Xenotransplantation of nude mice was conducted to detect the effects of circRNA_000864, miR-361-3p, and BTG2 on tumor growth.

Results

CircRNA_000864 and BTG2 were poorly expressed, and miR-361-3p was highly expressed in the pancreatic cancer tissues. CircRNA_000864 bound to miR-361-3p could target BTG2. Cell proliferation, migration, and invasion were inhibited, and the cell cycle arrest and apoptosis were stimulated after overexpression of circRNA_000864 or BTG2 or downregulation of miR-361-3p. Overexpression of circRNA_000864 or downregulation of miR-361-3p also decreased the tumor growth in vivo.

Conclusions

Conjointly, our findings elicited that the overexpression of circRNA_000864 could promote BTG2 expression to inhibit pancreatic cancer development by binding to miR-361-3p, which represents an appealing therapeutic target for the treatment of pancreatic cancer.

Tumor promoting effects of circRNA_001287 on renal cell carcinoma through miR-144-targeted CEP55

Background

Renal cell carcinoma (RCC) is a common urological cancer. circular RNAs (circRNAs) is involved in the development of various types of cancers. However, the roles and underlying mechanisms of circRNAs in RCC are not fully elucidated. Herein, we aimed to examine the potential effect of circ_001287 on RCC progression.

Materials and Methods

Microarray-based gene expression profiling of RCC was initially employed in order to identify differentially expressed genes. Next, the expression of circ_001287 was examined, and the cell line with the highest circ_001287 expression was selected for subsequent investigation. The interaction among circ_001287, miR-144, and CEP55 was identified by conducting luciferase reporter assay, RNA-pull down, RIP, RT-qPCR and FISH. The effect of circ_001287 on proliferative, invasive and migratory capacities as well as tumorigenicity of transfected cells in mice was examined using gain- and loss-of-function experiments.

Results

circ_001287 and CEP55 were highly expressed while miR-144 was decreased in RCC tissues and cell lines. circ_001287 can up-regulate CEP55 by binding to miR-144, which resulted in increased proliferative, invasive and migratory capacities and tumor growth in vivo. In addition, down-regulation of miR-144 was also observed to promote these biological activities.

Conclusions

Overall, these results elucidate a new mechanism for circ_001287 in RCC development and provide a potential therapeutic target for RCC patients.

Circ-TCF4.85 silencing inhibits cancer progression through microRNA-486-5p-targeted inhibition of ABCF2 in hepatocellular carcinoma

The current study aimed to explore the role of the circular RNA circ‐TCF4.85 and its downstream target microRNA‐486‐5p (miR‐486‐5p) in hepatocellular carcinoma (HCC) development. Circ‐TCF4.85 was detected to be highly expressed in HCC tissues. Next, we found that silencing of circ‐TCF4.85 repressed HCC cell proliferation, invasion, and migration, while enhancing apoptosis. In addition, biotin‐coupled probe pull‐down and miRNA capture assays, as well as fluorescence in situ hybridization, confirmed that circ‐TCF4.85 could bind to miR‐486‐5p. In rescue experiments, miR‐486‐5p had the potential to eliminate the tumor‐suppressive effects of circ‐TCF4.85 knockdown in HCC. Moreover, miR‐486‐5p was shown to target ABCF2 gene, which was positively regulated by circ‐TCF4.85. Finally, nude mice subcutaneously injected with si‐circ‐TCF4.85‐transfected HCC cells presented with inhibited xenograft tumor formation in vivo. Taken together, our results reveal that silencing of circ‐TCF4.85 suppresses HCC progression via miR‐486‐5p‐targeted inhibition of ABCF2.